Hello, I didn't find a DVB-S driver for the Neotion Pilot (aka @Sky Pilot with @SkyChip, USB v1.0), so I decided to write it on my own. In my german blog http://satfreak.blog.de/ I write something about the reverse engineering process. Now I've a problem with the 1-byte-checksum calculation. Each message which I send to the device has a checksum (last byte). I don't know how to calculate the checksum. Did someone know how to reverse engineer a 1-byte-checksum? Did someone see these type of messages before? Did someone detect any algorithm in the checksum values? Here are examples: static unsigned char ep03_msg109[] = { 0x81, 0x05, 0x01, 0x00, 0x02, 0x01, 0x06, 0x00, 0x01, 0xd0, 0x1e, 0x01, 0x00, 0xca /* Checksum */ }; static unsigned char ep03_msg110[] = { 0x81, 0x05, 0x01, 0x00, 0x02, 0x01, 0x06, 0x00, 0x01, 0xd0, 0x1f, 0x01, 0x00, 0xcb /* Checksum */ }; In the above example the checksum is incremented by one and there is also one byte incremented by one in the payload (0x1e -> 0x1f and 0xca -> 0xcb). this seems to be a simple addition. static unsigned char ep03_msg111[] = { 0x81, 0x05, 0x01, 0x00, 0x02, 0x01, 0x06, 0x00, 0x01, 0xd0, 0x20, 0x01, 0x00, 0xf4 /* Checksum */ }; In the next example the byte is further incremented, but the checksum changes much more (0x1f -> 0x20 and 0xcb -> 0xf4). The device doesn't respond to a message with the wrong checksum. I used this to try all values until I found the correct one, but this needs some seconds. This behaviour will not be acceptable within a DVB driver. Much more examples are in my test code which currently uses libusb-1.0: http://www.pastie.org/519407 Best regards Juergen Urban _______________________________________________ linux-dvb users mailing list For V4L/DVB development, please use instead linux-media@xxxxxxxxxxxxxxx linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
